Collector box for a motor vehicle

ABSTRACT

A collector box for a motor vehicle includes a collector for receiving heat exchange tubes and a cover mounted on the collector. The collector box extends in a longitudinal direction and has a cross section with a maximum height (h) and a maximum width (l). The collector is a metal profile delimited at its longitudinal ends by two end walls which extend in a substantially transverse plane. These two end walls are mounted on the metal profile, and the maximum height (h) of the collector box is greater than or equal to at least one and a half times the width (l) of the collector.

The present invention concerns the technical field of heat exchangers for motor vehicles, and more specifically concerns a collector box for such exchangers.

The collector box concerned is intended to be used for example in radiators of auxiliary cooling circuits, in particular in cooling circuits for supercharger air, batteries or electronic circuits.

In general, a collector box used in a heat exchanger comprises a collector for receiving heat exchange tubes, on which a cover is mounted which may be made of metal or plastic. The function of such a collector box is to distribute and pass fluid through the heat exchange tubes or to collect fluid leaving the tubes.

Collector boxes are designed as a result of specific constraints of heat exchange, and therefore require a specific design for each application, such that there is a wide variety of collector boxes for motor vehicles. For example, a collector box for a radiator differs from a collector box for a condenser. In fact for a radiator, the configuration of the box is very specific and depends on its application: depending on the flow required, relatively large boxes may be necessary to reduce the load loss. The collectors of these boxes are generally produced by deep-drawing. However for a condenser, the collector box must generally be very small and more or less circular in order to resist the high pressures applied to a condenser. The collectors of these boxes are generally metal profiles produced by the kilometer.

This variety of collector boxes is costly because it requires additional and different steps and means of implementation for each heat exchanger designed for a motor vehicle.

The object of the present invention is in particular to produce a collector box using as many standard parts as possible so as to reduce the costs of production and design while obtaining relatively low load losses and improving the thermal efficiency of a heat exchanger fitted with such a collector box.

To this end, the object of the invention is a collector box for a motor vehicle, comprising a collector for receiving heat exchange tubes, and a cover mounted on the collector, the collector box extending in a longitudinal direction and having a cross section with a maximum height (h) and a maximum width (l), the collector being a metal profile delimited at its longitudinal ends by two walls extending in a substantially transverse plane, called the end walls, these end walls being mounted on the metal profile, the maximum height (h) of the collector box being greater than or equal to at least one and a half times the maximum width (l) of the collector.

The ratio greater than or equal to 1.5 between the height and the width of the collector box allows homogenization of the speeds of the fluid flowing in each radiator tube. The result of this is to improve the thermal efficiency of the radiator. It is noted that the term “curved part” means a part which is not straight.

Thus a collector box is proposed which is configured to be used in a radiator while comprising a collector for a condenser. In fact the height of the box is relatively large since it is at least one and a half times greater than the width of the collector, and hence sufficient to reduce the fluid load loss and be used in a radiator while comprising a collector with the conventional configuration of a condenser: the collector is a metal profile which can be produced by the kilometer and on which end walls are mounted, in contrast to a traditional collector for a radiator which is produced by deep-drawing and therefore comprises end walls of the same material as the rest of the collector. In other words, the collector of the collector box described above may be used as such in a condenser, since it has a standard collector form which can be used both in a radiator and in a condenser. This is particularly advantageous insofar as it is no longer necessary to produce for example a specific collector for the design of a cooling radiator of an auxiliary circuit, since that provided for a condenser may be used. This substantially reduces the costs of design, supply of specific elements, production and implementation.

Also, since the collector is a metal profile on which the side walls are mounted, it may be produced by cutting from a long profile produced by the kilometer, which is less costly than deep-drawing.

Another advantage of such a collector box is that its size need not be increased too greatly since condenser collectors generally occupy a smaller volume than the collectors normally produced for radiators.

The collector box as defined above may also comprise one or more of the following characteristics, taken alone or in combination.

In a cross section, the collector has a contour comprising at least one curved part extending over a length L_(curve), this length L_(curve) being greater than or equal to 40% of the maximum width (l) of the collector box. This form of collector, although intended here to be used in a radiator, is suitable for use for a condenser because sufficiently curved forms, or quasi-circular, are necessary to resist the high pressures applied to a condenser.

The end walls are walls brazed or crimped onto the profile. This facilitates production of the collectors compared with the radiator collectors normally used, which are produced by deep-drawing.

The cover is made of metal. One particular advantage lies in that the cover takes up less space inside the collector for its connection to the collector than in the case where the cover is made of plastic, and consequently the maximum width of the collector is reduced, bringing it close to the width of the heat exchange tubes. In fact in the case where the cover is made of plastic, the collector must have a width close to 10 mm on either side of the adjacent tubes, whereas in the case of a metal cover this width may be nearer 3 or 4 millimeters. Therefore a collector with the width of a condenser collector may be used for a radiator. Also the strength of such covers is greater than that of plastic covers and they can be brazed directly onto the collector.

The object of the invention is furthermore a radiator for a motor vehicle, comprising a collector box as presented above. The radiator may also comprise one or more of the following characteristics, taken alone or in combination.

The radiator comprises heat exchange tubes, the heat exchange tubes being extruded tubes. These tubes are generally used for condensers and their heat exchange performance is superior to that of the tubes normally used in conventional radiators.

The cover of the collector box has a cross section with a maximum inner width (l_(i)), the tubes having a maximum outer width (l_(t)) in this cross section, the inner width (l_(i)) of the cover being very slightly greater than the maximum maximum width (l_(t)) of a tube, this width being preferably defined such that l_(i)≦l_(t)+5 mm (millimeters), and preferably l_(i)≦l_(t)+2 mm. Thus the cover has a width which is only very slightly greater than that of the tubes, which optimizes the compactness of the collector box and hence facilitates the positioning of the collector box in a motor vehicle.

The radiator comprises heat exchange fins arranged between the tubes.

The tubes have a width of between 10 and 22 millimeters, preferably between 12 and 16 millimeters. This width is defined preferably as the maximum outer width of the tubes.

The radiator is configured to cause the circulation of a fluid comprising water or water and an ethylene-glycol mixture.

The object of the invention is furthermore a method for production of a collector for a collector box as presented above, during which the collector is obtained by production of a metal profile, comprising a profiling step followed by a cutting step. In other words, the collector is produced by means of a profile produced by the kilometer. Thus such a production method gives a radiator with a significantly reduced cost price.

The invention will be better understood from reading the attached drawings which are given as examples and have no limitative character, and in which:

FIG. 1 is a diagrammatic perspective view of a collector box according to one embodiment, and

FIG. 2 is a diagrammatic cross section view of a collector box similar to that in FIG. 1, in a cross section plane.

FIG. 1 shows a collector box 10 for a heat exchanger, intended more specifically to be used on a radiator of an auxiliary cooling circuit. The radiator is configured here to cause the circulation of water and an ethylene-glycol mixture. The collector box 10 comprises a collector 12 for receiving heat exchange tubes 14 and also comprises a cover 16 mounted on the collector 12.

In the present description, the collector box 10 extends in a longitudinal direction Y and has a cross section defined by the intersection of the collector box 12 with a plane (X, Z) perpendicular to the longitudinal direction Y. The cross section of the collector box is defined by a maximum height h and a maximum width l. In this example, the maximum height h is at least one and a half times greater than the maximum width l, i.e. h is close to 30 millimeters and l is close to 19 millimeters. However it is conceivable to have a maximum height h which is greater than twice the maximum width l.

The collector 12 is a metal profile, delimited at its longitudinal ends by two walls 13 extending in a transverse plane, called the end walls 13, these two end walls being mounted on the metal profile. In other words, the walls 13 are not produced by deep-drawing from a metal plate forming the collector. The collector 12 used here is a type of collector which is normally designed to function on a condenser. In the example, these end walls 13 are brazed, however it is possible to crimp or weld them.

It is evident that, in the cross section, the contour of the metal profile which constitutes the collector 12 is substantially U-shaped. This profile is delimited by two curved portions 18 linked together by a straight lower portion 20, and possibly extended upward by two lateral straight portions 22. Each curved portion has a length corresponding to ½ L_(curve), so that the sum of the lengths of the curved portions 18 corresponds to a length L_(curve) which advantageously is greater than 40% of the maximum width l of the collector box 12. However, in other possible cases, this length L_(curve) could also be substantially equal to 40% of the maximum width l of the collector box.

In its lower portion 20 and rounded portions 18, the collector 12 is provided with mutually parallel transverse notches 24 which are arranged at regular intervals in the longitudinal direction of the collector. These notches 24 receive the heat exchange tubes 14 which are produced by extrusion and are preferably fixed to the collector 12 by brazing.

Between the tubes are heat exchange fins which improve the thermal exchange efficiency of the radiator.

In the example, the cover 16 of the collector box 12 is made of aluminum but it could also be made from other metals. It has a contour in cross section which is globally U-shaped, the top of which is flared, and is provided with a flat base 26 and two side walls 28. The ends of the side portions 28 of the cover are preferably slightly flared and brazed to the ends of the metal profile, with two lateral brazing beads 30 which extend longitudinally relative to the collector box.

With reference to FIG. 2, we see that in the cross section of the collector, the cover 13 of the collector box 12 has an inner width l_(i), the tubes 14 have a maximum outer width l_(i), and the inner width l_(i) is slightly greater than the maximum width l_(t). In the example, the tubes have a width l_(t) which is 14 millimeters but their width could be different and lie between 10 and 22 millimeters, preferably between 12 and 16 millimeters.

A collector as described above is produced by a method comprising a profiling step followed by a cutting step. The profiling step is performed by passing a metal strip between successive pairs of rollers until a substantially U-shaped form is obtained, as defined above. The profile is then cut to the length necessary to produce the collector box. The notches are produced at the same time.

The invention is not limited to the embodiments presented above and other embodiments will appear more clearly to the person skilled in the art. In particular it is possible that the width l, is preferably defined such that l_(i)≦l_(t)+5 millimeters, and preferably l_(i)≦l_(t)+2 millimeters. 

1. A collector box for a motor vehicle, comprising: a collector for receiving heat exchange tubes; and a cover mounted on the collector, the collector box extending in a longitudinal direction and having a cross section with a maximum height and a maximum width, the collector being a metal profile delimited at its longitudinal ends by two walls extending in a substantially transverse plane, called the end walls, the two end walls being mounted on the metal profile, wherein the maximum height of the collector box is greater than or equal to at least one and a half times the maximum width of the collector.
 2. The collector box as claimed in claim 1, wherein the collector in a cross section has a contour comprising at least one curved part extending over a length L_(curve), this length L_(curve) being greater than or equal to 40% of the maximum width (l) of the collector box (10).
 3. The collector box as claimed in claim 1, wherein the end walls (13) are brazed or crimped onto the profile.
 4. The collector box as claimed in claim 1, wherein the cover is made of metal.
 5. A radiator for a motor vehicle, comprising a collector box as claimed in claim
 1. 6. The radiator as claimed in claim 5, further comprising heat exchange tubes, wherein the heat exchange tubes are extruded tubes.
 7. The radiator as claimed in claim 5, wherein the cover of the collector box has a cross section with a maximum inner width, the tubes having a maximum outer width in this cross section, the inner width of the cover being very slightly greater than the maximum width of a tube, this width being defined such that l_(i)≦l_(t)+2 mm (millimeters).
 8. The radiator as claimed in claim 5, comprising heat exchange fins arranged between the tubes.
 9. The radiator as claimed in claim 5, wherein the tubes have a width between 10 and 22 millimeters, preferably between 12 and 16 millimeters.
 10. The radiator as claimed in claim 5, configured to cause the circulation of a fluid comprising water or water and an ethylene-glycol mixture.
 11. A method for production of a collector for a collector box as claimed in claim 1, during which the collector is obtained by production of a metal profile, comprising a profiling step followed by a cutting step. 